Photodegradation of toluene over TiO(2-x)N(x) under visible light irradiation

We report the photooxidation of toluene over nitrogen doped TiO(2) (TiO(2-x)N(x)) under visible light irradiation. The photocatalytic oxidation of toluene in air over TiO(2-x)N(x) powders was studied using diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS), gas chromatography (GC), ion chromatography (IC), and gas chromatography mass spectrometry (GC-MS), focusing on the photocatalytic decomposition processes of toluene. Results obtained indicate that toluene, weakly adsorbed on the catalyst surface, is initially photooxidized to benzaldehyde which adsorbs onto the TiO(2-x)N(x) surface more strongly, leading to the formation of ring-opening products such as carboxylic acids and aldehydes. No gaseous intermediates were detected during the photooxidation. Major intermediates adsorbed at the catalyst surface were oxalic acid, (COOH)(2), acetic acid, CH(3)COOH, formic acid, HCOOH, and pyruvic acid, CH(3)COCOOH, whereas more complicated carboxylic species, including propionic acid, CH(3)CH(2)COOH, isovaleric acid, (CH(3))(2)CHCH(2)COOH, and succinic acid, (CH(2)COOH)(2), were also found in the early stage of the photooxidation. These intermediate products were gradually photodegraded to CO(2) and H(2)O under visible light irradiation.     

N+NO reaction on Rh(111) surfaces studied with fast near-edge X-ray absorption fine structure spectroscopy: role of NO dimer as an extrinsic precursor

We studied the mechanism of the N+NO reaction on Rh(111) surfaces by means of fast near-edge X-ray absorption fine structure spectroscopy. This reaction is important as a basis of NOx reduction reactions on platinum-group metal surfaces. Atomic nitrogen layers on Rh(111) were titrated with NO at various temperatures. N2O is exclusively formed and desorbs into the gas phase below 350 K. The consumption rate of atomic nitrogen exhibits strange temperature dependence between 100 and 350 K; the reaction proceeds slower with increasing temperature. Reaction kinetics analyses and isotope-controlled experiments have revealed that the surface N atoms do not react with chemisorbed NO molecules but with NO dimers weakly bound on top of the chemisorbed layer, which play a role as an extrinsic precursor. The present results may support the possibility that NO dimers participate in various NO-related synthetic, biochemical, and surface reactions as an intermediate.     

Presence and origin of large amounts of d-proline in the urine of mutant mice lacking d-amino acid oxidase activity

Using a column-switching HPLC system combining a micro-ODS column and a chiral column, the amounts of d-proline (d-Pro) have been determined in 18 tissues, plasma and urine of mice. To avoid the enzymatic degradation of d-amino acids in vivo, a mutant mouse strain lacking d-amino acid oxidase activity (ddY/DAO⁻ mouse) was used. In the brain, relatively large amounts of d-Pro were observed in the anterior pituitary, posterior pituitary and pineal glands. In the peripheral tissues, the amounts of d-Pro were high in the pancreas and kidney. Above all, it is surprising that the ddY/DAO⁻ mice excreted large amounts of d-Pro in their urine (433 nmol/mL, 20 times that of l-Pro). The origin of d-Pro has also been investigated. By comparing germ-free mice and gnotobiotic mice, intestinal bacteria were shown to have no effect on the urinary d-Pro amount. Concerning the dietary origin, a notable amount of d-Pro was still excreted in the urine after starvation for 4 days, suggesting that some of the d-Pro is produced in the mice. Age-dependent changes in the urinary d-Pro amount have also been investigated from the postnatal 1st month up to 12 months, and ddY/DAO⁻ mice were found to excrete large amounts of d-Pro in the urine constantly throughout their lives. Kenji Hamase is Associate Professor in the Department of Bioanalytical Chemistry, Graduate School of Pharmaceutical Sciences at Kyushu University. His current research interests focus on the development of analytical methods for d-amino acids and the study of their physiological functions and diagnostic values. He received the Japanese Society for Analytical Chemistry Award for Young Scientists in 2003, and the PSJ Award for Young Scientists in 2006.     

Regio- and stereoselective nickel-catalyzed homoallylation of aldehydes with 1,3-dienes

Ni(acac)(2) catalyzes homoallylation of aldehydes with 1,3-dienes in the presence of triethylborane. Triethylborane serves as a reducing agent delivering a formal hydride to the C2 position of 1,3-dienes, thus generating a formal homoallyl anion species and enabling the novel homoallylation of aldehydes. The reaction proceeds smoothly at room temperature in the absence of any phosphane or nitrogen ligands and is highly regioselective and stereoselective for a wide variety combination of aldehydes and 1,3-dienes: e.g., isoprene and benzaldehyde combine to give a mixture of anti- and syn-1-phenyl-3-methyl-4-penten-1-ol (2.2) in a ratio of 15:1 in 90% yield. Under the conditions, sterically congested aliphatic aldehydes and ketones show low yields. In such cases, diethylzinc serves as a substitute for triethylborane and yields the expected products in good yields with similarly high regio- and stereoselectivity. 1,3-Cyclohexadiene is one exception among 24 kinds of dienes examined and undergoes allylation (not homoallylation) selectively.     

Quantum-like dynamics of decision-making

In cognitive psychology, some experiments for games were reported, and they demonstrated that real players did not use the “rational strategy” provided by classical game theory and based on the notion of the Nasch equilibrium. This psychological phenomenon was called the disjunction effect. Recently, we proposed a model of decision making which can explain this effect (“irrationality” of players) Asano et al. (2010, 2011) [23] and [24]. Our model is based on the mathematical formalism of quantum mechanics, because psychological fluctuations inducing the irrationality are formally represented as quantum fluctuations Asano et al. (2011) [55]. In this paper, we reconsider the process of quantum-like decision-making more closely and redefine it as a well-defined quantum dynamics by using the concept of lifting channel, which is an important concept in quantum information theory. We also present numerical simulation for this quantum-like mental dynamics. It is non-Markovian by its nature. Stabilization to the steady state solution (determining subjective probabilities for decision making) is based on the collective effect of mental fluctuations collected in the working memory of a decision maker.     

Asymptotic Theory for the Time-Dependent Behavior of a Slightly Rarefied Gas Over a Smooth Solid Boundary

A time-evolution of a slightly rarefied monoatomic gas, namely a gas for small Knudsen numbers, which is perturbed slowly and slightly from a reference uniform equilibrium state at rest is investigated on the basis of the linearized Boltzmann equation. By a systematic asymptotic analysis, a set of fluid-dynamic-type equations and its boundary conditions that describe the gas behavior up to the second order of the Knudsen number are derived. The developed theory covers a general intermolecular potential and a gas-surface interaction. It is shown that (i) the compressibility of the gas manifests itself from the leading order in the energy equation and from the first order in the continuity equation; (ii) although the momentum equation is the Stokes equation, it contains a double Laplacian of the leading order flow velocity as a source term at the second order; (iii) a double Laplacian source term also appears in the energy equation at the second order; (iv) the slip and jump conditions are the same as those in the time-independent case up to the first order, and the difference occurs at the second order in the jump conditions as the terms of the divergence of flow velocity and of the Laplacian of temperature. Numerical values of all the slip and jump coefficients are obtained for a hard-sphere gas by the use of a symmetric relation developed recently.